SPC MD 1749
SPC MD 1749
[html]MD 1749 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTH AND SOUTH DAKOTA

Mesoscale Discussion 1749
NWS Storm Prediction Center Norman OK
0303 PM CDT Tue Jul 30 2024
Areas affected...North and South Dakota
Concerning...Severe potential...Watch possible
Valid 302003Z - 302200Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorm development is anticipated in the next 1-2
hours across the western Dakotas. Storms are expected to intensify
as they migrate east into central North and South Dakota. Watch
issuance is possible later this afternoon/evening as the severe
threat beco*es more prominent.
DISCUSSION...Recent GOES visible imagery shows a gradual increase in
cumulus along a surface trough and within the Black Hills in western
SD. Mid to upper-level cirrus overspreading the region from the west
is indicative of gradually increasing synoptic-scale ascent ahead of
a mid-level shortwave trough over ID/MT. Thunderstorm development
appears likely in the co*ing hours as ascent continues to increase
and continued daytime heating erodes any lingering MLCIN.
Initial thunderstorms across the western Dakotas will develop within
a relatively dry/well-mixed environment with LCL heights between 3.0
to 3.5 km. This environment will favor strong downdraft
accelerations and rapid cold pool development/expansion with an
attendant severe wind risk. Convection is expected to intensify as
it moves east through the evening hours and encounters a reservoir
of richer low-level moisture (well-sampled by a recent 19 UTC ABR
sounding). Adequate deep-layer wind shear (around 30-35 knots)
should support organized convection. Storm coverage remains somewhat
uncertain given weak forcing for ascent. While the environment may
support a supercell or two this evening, clustering of initial cells
is possible and may promote upscale growth and a more robust wind
threat. Trends will be monitored and watch issuance may be needed
later this afternoon or evening to address this concern.
..Moore/Gleason.. 07/30/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...BIS...UNR...
LAT...LON 44930049 44030188 43840218 43790254 43850287 44170313
44510327 44810330 46100323 46540311 46740298 47060283
47900222 48380147 48400078 48060016 47429973 46649967
46039979 45490003 44930049
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Source: SPC MD 1749 (http://ht**://www.spc.noaa.gov/products/md/md1749.html)